1. Field of the Invention
This invention relates to a device and method for activating a switch, and in particular, the invention relates to a removable and adjustable switch actuator for remote activation of a switch handle, or toggle, and a method for remote activation of a switch or toggle.
2. Background of the Invention
Toggling or actuation of electrical switches is common place. However, significant danger is created by the toggling of switches associated with high-current circuits. The danger stems from the sudden breakdown of voltage resistance of the air surrounding the switch. Normally, air is a good insulator, however, the resistivity of air may be overcome if air provides the optimum path to ground and a sufficiently-large electrical current exists.
The passage of electrical current through air creates arcs. Electrical arcs have practical uses, such as in welding, plasma cutting, or as a light source; however not all electrical arcs are desirable. Unintentional electrical arcs formed by high voltage and high current electrical discharges result in particularly dangerous events called arc flashes.
Arc flashes are potentially destructive events releasing large amounts of energy in the form of light and heat. While arc flashes are possible only in some environments (above 480 Volts (V)), the resulting potential injury and risk of damage is unacceptable. For example, industrial equipment such as loading devices commonly use three-phase connections resulting in voltage potential differences of at least 480 volts. If a sufficiently large fault current occurs on such a circuit, the amount of energy released by a resulting arc flash could be catastrophic. Continuing the example, if at 480 Volts, 10,000 Amperes of fault current continues for 10 cycles at 60 Hz, the resulting arc flash would release 0.8 mega joules of energy. By comparison, a hand grenade releases about 0.6 mega joules of energy. While much of the energy released by an arc flash event (radiant energy) is different from a chemical explosion (mechanical shock), both are highly dangerous inasmuch as both produce significant pressure/shock waves that violently propel solid or molten material outward.
The actuation of electrical switches, such as circuit breakers, is especially prone to arc flash events. Upon actuation, the flow of current is interrupted. However, as no switch operates instantly, an ungrounded fault current develops prior to the flow of current ceasing. While it may dissipate harmlessly, arc flashing is also possible resulting in injury to the operator and property damage.
The danger posed by arc flash events has been recognized by worldwide engineering bodies and safety groups. For example, IEEE 1584-2002, Guide for Performing Arc Flash Hazard Calculations, IEEE Industry Applications Magazine, January-February 2005, pages 23-31 provides a method of calculating the level of arc-flash hazard dangers in several scenarios. This industry standard further recommends personal protective equipment (PPE) and specifies a safe working distance. Similarly, the National Fire Protection Association (NFPA) Standard 70-2002 “The National Electrical Code” (NEC) specifies the required warning labels and OSHA Standards 29-CFR, Part 1910 addresses standards for workplaces.
One of the most common means of protecting personnel from arc-flash injury is the use of protective apparel. This apparel can be insulated gloves and full body suits. These suits are aptly named “bee keeper” suits. Due to their insulating capacity, the suits are both uncomfortable to wear and are also expensive. Further, the protective suits require time to don and subsequently remove, even if the switch actuation requires no more than a few seconds. In environments where the ambient temperatures exceed approximately 60° F., these suits cause the wearers to perspire excessively.
The inconvenience of donning bulky protective suits results in their being used less frequently.
A need exists in the art for a method and device for actuating electrical and thermal switches and toggles quickly from safe distances. The method and device should facilitate remote actuation so as to obviate the need for protective apparel. The method and device should adapt to various switch gear configurations and housings. Furthermore, the method and device should electrically and/or thermally insulate the user from arcing or outgassing.